golf93871

Global warming is a reality and increasingly its consequences are upon us. We may think that global warming does not affect us but the fact is it has already started to have disastrous consequences. flash floods, droughts, receding icebergs, cyclones are some of the manifestations of global warming. Although we are aware and worried about it and trying our best to control it but no significant impact could be seen.

Scientists have come up with new strategies to tackle the problem. Now a scientist has suggested an ambitious idea to contain global warming. put sunshades in space. Thats right. University of Arizona astronomer Roger Angel suggests putting sunshades in space and has detailed his idea in a paper Feasibility of cooling the Earth with a cloud of small spacecraft near L1 in the Proceedings of the National Academy of Sciences. He suggests launching a constellation of trillions of small free-flying spacecraft a million miles above Earth into an orbit aligned with the sun, called the L-1 orbit.

This spacecraft would form a long, cylindrical cloud and would have a diameter about half that of Earth, and about 10 times longer. It is suggested that about 10 percent of the sunlight passing through the 60,000-mile length of the cloud, pointing lengthwise between the Earth and the sun, would be diverted away from our planet. This would result in uniformly reduced sunlight by about 2 percent over the entire planet and would balance the heating of carbon dioxide in Earth's atmosphere.

The use of space shade was first mooted by James Early of the Lawrence Livermore National Laboratory in 1989.

"The earlier ideas were for bigger, heavier structures that would have needed manufacture and launch from the moon, which is pretty futuristic," Angel said. "I wanted to make the sunshade from small 'flyers,' small, light and extremely thin spacecraft that could be completely assembled and launched from Earth, in stacks of a million at a time. When they reached L1, they would be dealt off the stack into a cloud. There's nothing to assemble in space."

Angel proposes to design lightweight flyers made of transparent film pierced with small holes and would be two feet in diameter, 1/5000 of an inch thick and weigh about a gram, the same as a large butterfly. He suggests using MEMS technology mirrors as tiny sails that tilt to hold the flyers position in the orbiting constellation.

The weight of all flyers would be 20 millions tons. But conventional rocket launch system at $10,000 a pound would be too prohibitive. His alternative would cost only around $20 a pound.

He suggests deploying a total 20 electromagnetic launchers launching a stack of flyers every 5 minutes for 10 years. The electromagnetic launchers would use hydroelectric power but even if it uses coal-generated electricity, each ton of carbon used would reduce the effect of 1000 tons of atmospheric carbon.

Once propelled beyond Earths atmosphere the flyer stacks would be steered to L-1 orbit by solar-powered ion propulsion, pioneered by European Space Agency's SMART-1 moon orbiter and NASA's Deep Space 1 probe.

"The concept builds on existing technologies," Angel said. "It seems feasible that it could be developed and deployed in about 25 years at a cost of a few trillion dollars. With care, the solar shade should last about 50 years. So the average cost is about $100 billion a year, or about two-tenths of one percent of the global domestic product."

He added, "The sunshade is no substitute for developing renewable energy, the only permanent solution. A similar massive level of technological innovation and financial investment could ensure that.

"But if the planet gets into an abrupt climate crisis that can only be fixed by cooling, it would be good to be ready with some shading solutions that have been worked out."

Syndicated By : http://pressreleasegold.com

Contact : syndication@pressreleasegold.com

Deepak Purang writes on Science & Technology and edits Science & Technology website http://pressreleasegold.com.

Sciatica can be helped, it can at times be helped by you and other times you need help. There are 3 things you need to know so you can understand what you can do or whether you need help.

Sciatica is often confused. It can be a serious condition or it may be an irritation that is easily corrected. How do you know? If know the answer to three questions, then you can decide whether you can correct your sciatica yourself or you need to seek help from a structural specialist.

The questions are as follows:

1. How far does your sciatica travel?

The sciatic nerve can be irritated in the lower back, pelvis and as a result of muscular tightness in the buttock. If you have lower back pain and pain travels out to the buttock, this can still be sciatica. It is just a lesser form and easily corrected with various lower back stretches, exercises and joint techniques. If your lower back pain travels down the leg to your foot or ankle, then obviously the sciatic nerve is irritated at a greater level. The further your sciatica travels, generally speaking, the worse the condition. In these situations professional advice and treatment is indicated.

2. What type of sciatic pain to do you have?

Pain type is indicative of severity. Most people with sciatica will experience pain, it may be a gnawing, and toothache feeling or it may throb or shoot down the leg. Others will have a numb feeling and some may experience the muscles not holding their strength. If you look at the type of pain, you can see how serious it is. Nerves, when irritated, exhibit definite pain patterns. The outer fibers of the nerve create what is called paraesthesia which mean altered sensation. You may experience tingling, the gnawing feeling and a sensation of numbness. The numbness is a sensation not a reality. You can check this by pinching the area or using a pin prick. If you still feel pain with these then you have paraesthesia not true numbness.

The deeper layers of the nerve then cause the sharper, definite pain. The deepest levels will cause actual numbness and loss of muscle power, strength and endurance.If you experience symptoms of the deeper layer disturbances, then professional help is essential. The lesser pain types can be usually corrected with many self help exercises.

3. How did your sciatica happen?

If you have had a fall or injury then sciatica needs attention. Sciatica at times is caused by disc injuries and spinal conditions that relate to joint instability. These need to be assessed and treated accordingly. Although the majority of sciatic nerve irritation comes after situations that appear completely normal. Your normal daily activity should not cause sciatica, however a build up of tension can lead to sciatic nerve problems.

If you have not had trauma, if your general health is generally okay, your sciatica will most likely respond to some simple self help techniques you can use at home. It can ease and disappear quickly but as the saying goes .if pain persists see your doctor . Sciatica is common and easily corrected. If you fit the criteria of caution, then be cautious and seek professional intervention. Otherwise correct your sciatica yourself with some simple and easy sciatica techniques.

Dr Graeme Teague is an expert in the structural field, and has been in practice since 1991. His newly launched web site The Back Pain Advisor - strives to give you valuable and expert advice, tips and information on your back pain issues.

For more information on Sciatica issues just visit Sciatica -

Subscribe to your free e-course on solutions to your back pain, just click here - Back Solutions